Lung cancer is the leading cause of cancer death in men and women in the United States. Non-small cell lung cancer (NSCLC) accounts for more than 87% of all lung cancers diagnosed in the U.S. Despite major advances in recent years, most lung cancers have disseminated at the time of presentation and affected individuals have a mortality rate of nearly 90%.
This high mortality is mainly due to the absence of an effective screening strategy to identify lung cancer at an early curable stage. Thus, only ˜25% of patients presenting with lung cancer are in a sufficiently early stage to be amenable to effective surgical treatment. The patients with stage I or II NSCLC have an ˜50% five year survival rate after surgery alone, compared to less than 5% five-year survival rate for patients with advanced lung cancer (stages IIIb and IV).
Patients diagnosed with stage I NSCLC usually undergo surgical resection. Yet, nearly 50% of patients with stage I or II NSCLC will die from recurrent disease despite surgical resection. There are no reliable clinical or molecular predictors for identifying those at high risk for developing recurrent therapy. 
There is, therefore, a critical need in the art to identify a reliable molecular signature in the tumor that could identify those who are likely to develop recurrent disease. If such biomarkers are identified, adjuvant therapy could be selectively administered to those at high risk for relapse. Conversely, the low risk group can be spared the side effects of adjuvant therapy.